In radio frequency (RF) front-end modules, RF amplification devices provide amplification to RF signals. For example, an RF input signal in a transmission chain or a receiver chain in the front-end module may be amplified for further processing by downstream RF circuitry. Under ideal conditions, the RF amplification device may be provided so that a source impedance presented to downstream RF circuitry matches a load impedance presented by the downstream RF circuitry to the RF amplification device. This minimizes power dissipation at the RF amplification device and maximizes power transfer.
However, RF amplification devices often have to operate in less than ideal conditions. For example, the load impedance presented by the downstream RF circuitry may experience fluctuations, thereby resulting in excessive power dissipation by the RF amplification device and/or excessive signal levels that may damage the RF amplification device. Accordingly, to prevent excessive power dissipation and/or signal levels that may damage the RF amplification device, there is a need to limit the RF signal current generated by the RF amplification device.
Unfortunately, current limiting circuitry used to limit current in RF amplification devices is often complex. As a result, the current limiting circuitry may make the RF amplification device more expensive to manufacture. The complexity of the current limiting circuitry may also hinder performance. For example, this complexity may affect how fast the current limiting circuitry can respond and/or the degree to which the current limiting circuitry can limit the RF signal current. Therefore, there is a need for methods and circuitry that employ simpler techniques for limiting the RF signal current and/or can provide a higher degree of current limiting.